1. Field of the Invention
The present invention relates to a field effect transistor and a method of manufacturing the same, and more particularly to a field effect transistor which can operate stably at a microwave band including a millimeter wave band, and a method of manufacturing the same.
2. Description of the Related Art
Generally, a field effect transistor with a Schottky gate becomes unstable in the operation at a high frequency. That is, a K factor becomes 1 or below in a millimeter wave band depending on the operation condition of an field effect transistor so that the field effect transistor possibly oscillates. In order to eliminate the operation instability of the field effect transistor in this millimeter wave band, a resistance of several ohms has been conventionally inserted in the series with a gate circuit. In other words, the operation of the field effect transistor becomes unstable because a gate input impedance becomes low in the millimeter wave band. However, by addition of the resistance, a loss is inserted effectively. Therefore, the K factor can be made equal to or more than 1 by the resistance, and the operation stability of the field effect transistor can be attempted.
The resistance to be inserted in the series with the gate circuit is conventionally provided outside the field effect transistor. For this reason, a special space becomes necessary to form the resistance in the field effect transistor. Therefore, in the integrated circuit, this space functions as a bar against the small size of a device. Also, a special photolithography process becomes necessary to form the resistance. Therefore, the number of processes increases to cause the cost up.
In conjunction with the above, a multiple cell type micro wave field effect transistor is described in Japanese Laid Open Patent Application (JP-A-Showa 63-127575). In this reference, a plurality of unit cells are connected in parallel. A gate electrode and a drain electrode in one unit cell are connected with a gate electrode and a drain electrode in an adjacent unit cell via resistance bodies.
Also, a field effect transistor is described in Japanese Laid Open Patent Application (JP-A-Heisei 2-110943). In this reference, a resistance body is provided to connect between gate stripe electrodes or between drain stripe electrodes.